It is a great ride and the crowds of spectators on the well known climbs add to the experience. Personally I think it's best to start as early as you can as then you avoid the worst of the crowds on the actual climbs, but be prepared to get off and run on climbs like the Koppenberg and the Muur when people topple over in front of you and block the road. Once you've stopped on those narrow cobbled climbs you can get going again.
It is a great ride and the crowds of spectators on the well known climbs add to the experience. Personally I think it's best to start as early as you can as then you avoid the worst of the crowds on the actual climbs, but be prepared to get off and run on climbs like the Koppenberg and the Muur when people topple over in front of you and block the road. Once you've stopped on those narrow cobbled climbs you can get going again.